Cough and Swallow Rehab Following Stroke

Stroke is the leading case of neurologic swallow dysfunction, or dysphagia. Post stroke dysphagia is associated with approximately 50% increase in the rate of pneumonia diagnoses; aspiration pneumonia is the most common respiratory complication in all stroke deaths, accounting for a three-fold increase in the 30-day post stroke death rate. The long-term goal of this systematic line of research is to decrease the morbidity, mortality, and health care costs associated with disordered airway protection following stroke. The overall hypothesis central to this proposal is that the ability to protect the airway is dependent upon a continuum of multiple behaviors, including swallowing and cough. Safe, efficient swallowing prevents material from entering the larynx and lower airway, and effective cough ejects aspirate or mucus material. Currently, only one end of the continuum, swallowing, is rigorously assessed in stroke patients. However, ineffective or disordered cough is indicative of the inability to eject aspirate material or clear mucus and secretions from the lower airway. Ineffective clearance and subsequent accumulation of material in the lower airway increases the risk of chest infection. Hence, patients at the greatest risk for chest infection would not only have disordered swallowing (dysphagia) but also disordered cough (dystussia), meaning they are more likely to aspirate material and then cannot effectively eject the aspirate from the airway. There is a high likelihood that swallowing and cough are simultaneously disordered following stroke. To date, there is a treatment that targets both swallowing and cough function in stroke patients. Expiratory muscle strength training (EMST) increases expiratory muscle strength (Baker et al., 2005) and there is evidence that supports its use to improve both swallow and cough functions in patients with Parkinson's disease (Troche et al., in press). This cross-system, device-driven approach to rehabilitating multiple contributors to airway protection deficits is highly desirable in the stroke population due to the likelihood of the co-occurrence of both swallow and cough disorders. To date, EMST has not been tested in stroke patients. We propose that by including cough in the screening, evaluation and treatment processes for disorders of airway protection, we will be able to better identify and treat patients most at risk for airway compromise and associated sequelae.